Among network configurations in which information terminals are mutually connected, a wireless network that uses wireless communications has advantages over a wire network that uses wire communications in the following points. The wireless network has portability and the degree of freedom in the arrangement of the information terminals higher than those of the wire network, and can reduce the weights of the information terminals by removing wired cables. Thus, wireless communication apparatuses have been not only utilized for data transmission between conventional personal computers but also currently mounted in a lot of home electric appliances, and the wireless communication is utilized for video and audio data transmission among the home electric appliances.
The wireless communication apparatuses has the above-described advantages, however, sometimes failed in normally transmitting data due to deterioration in the transmission characteristics under the influence of fading caused by delay waves that arrive after being reflected on objects when the wireless communication apparatuses are placed in a space where a number of reflective objects are placed, since the wireless communication apparatuses communicate with each other by radiating electromagnetic waves in the space. For example, when an Internet Video on Demand (VoD: Video on Demand) technology is utilized by using fixedly installed home electric appliances, such as a large-sized television broadcasting receiver apparatus, a Blu-ray Disc recording and reproducing apparatus or a DVD recorder, it is required to mount a function of connection to a wireless LAN (Local Area Network) on each of the home electric appliances and to provide a wireless LAN access point for connection to an Internet line. In this case, the fading is mainly caused by the movement of a human being who exists in the periphery of the television broadcasting receiver apparatus or the DVD recorder, and opening and closing of doors. In addition, when wireless communication apparatuses that are mounted in portable equipments such as a small-sized television broadcasting receiver apparatus such as a one-segment television broadcasting receiver apparatus, a portable DVD player or the like, and a wireless access point communicate with each other, the fading is mainly caused when the equipments are moved.
Conventionally, as measures against such fading, there have been proposed control methods such as directivity control and a variety of diversity processing of transceiving antennas. For example, the Patent Documents 1 to 3 disclose prior art wireless communication apparatuses that receive wireless signals according to temporal changes in the radio wave propagation environment.
In addition, for the directivity control of the transceiving antennas, the following variable directivity antenna apparatus is proposed in the Patent Document 4. The variable directivity antenna apparatus has a feed antenna element and parasitic antenna elements, and one pair of PIN diodes is provided for each of the parasitic antenna elements. Inductors are provided at a predetermined interval in portions electromagnetically coupled to the other variable directivity antennas for each control line to connect the PIN diodes to a controller. The interval at which the inductors are provided is set to a length so that the interval between the inductors does not substantially resonate at the operating frequency of the variable directivity antenna.